Mine car wheel



I Dec. 4, 1934.

A. L. LEE

MINE CAR WHEEL Filed Jan. 16, 1933 2 Sheets-Sheet 1' I 4, 1934. f A 1 L1,983,177

MINE CAR WHEEL 7 Filed Jan. 16, 1933 2 Sheets-Sheet 2 Patented Dec. 4,1934 MINE CAR WHEEL Arthur L. Lee, Gibsonia, Pa.

Application January 16, 1933, Serial No. 651,902

4 Claims.

This invention relates to a wheel for mine and industrial cars.

Under present-day mining conditions, particularly in coal mines,automatic loading has caused 6 an increase in the size of mine cars anda more vigorous use of the cars, with increased speed at which the carsare propelled and an increased number of daily trips for each car. Underpresent practice mine cars are also increased in size 10 and loadedcapacity, and because of space limitation increased height of the .carshas been partially compensated for by decreased diameter of the carwheels.

.This modern mine practice has resulted in greatly decreasing the usefullife of mine car wheels, flat spots generally developing on the tread ofthe wheel in the third or fourth year of its use. I have discovered thatthe flat spots on the treads of the wheels occur in a particularlocation, which is diametrically outward of the wheel spokes, showingthat the wheel tread is less durable at these points. I have found thatthe presence of areas of less resistance to wear in the treads of thewheels results from the standard foundry practice by which mine carwheels are made, which practice I shall herein briefly describe.

Mine car wheels are made of cast iron, or an iron in which some smallpercentage of alloying metal is included. In casting the wheels a chill,in the form of a metallic band of considerable heat capacity, is sopositioned in the flask that it is in contact with the molten metalwhich solidifies to form the outer surface or tread of the wheel. Thefunction of this chill is to produce a rapid solidification of the treadmetal, so that the internal change, incident to the slow cooling of.cast iron does not occur, and a tread layer of white cast ironcontaining a relatively high percentage of combined carbon is formed inthe felly.

The hub of the wheel, however, is of considerable body, and the spokesleading from the hub to the felly of the wheel place the felly, in theTES PATENT OFFICE to avoid. On fracturing a wheel of the spoke form, socast, it is found that the chilled, or white, cast metal extendsinwardly from the tread surface a much lesser distance in the region ofeach of the spokes than in the regions which are not d'ametricallyadjacent a spoke.

A further undesirable effect present in the casting of a spoked wheel isthat the mass of metal constituting the hub and spokes contracts moreslowly than the body of metal forming the felly of the wheel. Stressesare thus set up due to the tendency for the spokes to pull away from thefelly. When this tendency is counteracted, as is usual, by placing thewheels in a soaking pit after casting, the annealing effect producesstructural changes in the metal decreasing the hardness of the chilledtread. If a disk wheel of usual form, having a disk disposed centrallyof the felly, is cast, there is a tendency for the disk to pull awayfrom the felly at all points, and such wheels must also be soaked inorder to relieve the stresses thus setup. In such a disk wheel also thedisk serves, similarly to thespokes, as a. heat feeder to the felly, andthus serves to decrease the thickness of the chilled tread metal allaround the wheel.

Since, moreover, the tread hardness, produced.

by use of a chill, extends uniformly throughout the width of the tread,as wheels have been previously made, the region of the tread width-whichis subjectedtothe greatest wearing effect wears more rapidly than theremaining width of the tread. Thus the treads of mine car wheels aspreviously made tend to channel in the circumferential region adjacentthe flange, in which region a wheel is in contact with the track.

In order to avoid these variousdisadvantageous features I have devised amine car wheel of such conformation that during the casting of the wheelcompensation is made for disadvantageous effects.

In my wheel,as a product of manufacture, the

tread hardness is of substantially uniform depth circumferentially ofthe wheel, with a relatively great thickness of chilled or white, metalin such portion of the width as is subjected to the greatest wearingeffect. The depth of chill moreover is roughly graduated from the regionadjacent the wheel flange to the outer edge of the tread, so that awheel wears with substantial uniformity throughout the width of thetread. It may be generally stated that mywheel is formed in conformitywith problems arising from the casting operation by which it isproduced, with the thought of producing a wheel in service.

of greatly increased life In the accompanying drawings Figure I is avertical sectional view through a foundry flask, illustrating thecasting of my specially shaped wheel; Figure II is an inner faceelevation of my wheel; Figure III is a vertical sectional view throughthe wheel itself as an article of manufacture, taken on the line III-IIIof Figure II; Figure IV is a fragmentary view, on an enlarged scale,illustrating the depth of chill throughout the tread width of my wheel;and Figure V is a vertical section through a foundry flask, illustratinga modification in the casting of my wheel.

My improved wheel comprises a hub 1 and felly 2 contoured as'is usual inmine car wheels. Instead of providing spokes, however, I form the wheelwith a disk 3 extending between the hub 1 and felly 2 of the wheel. I amaware that mine car wheels have been made of disk type with adiskjoining the hub and felly.

With reference particularly to Figure III of the drawings, it will beseen that my disk 3 is positioned at the outer edge of the felly, and isnot positioned, as is usual in such type of cast wheel, approximatelymidway of the width of the telly. As will be seen in Figure II, disk 3is of substantial thickness and its face lying inwardly, or toward theflange of the wheel, is dished, giving a greater depth or thickness ofmetal at the inner junction of the disk and felly. In order tostrengthen the structure I provide a plurality of webs 5 extendingangularly from the outer face of the disk to the hub of the wheel. Asshown these webs 5 have no contact with the felly 2 of the wheel, and itis of importance that they do not have contact with the felly of thewheel in any region closely adjacent the flange 4. The reason for thisarrangement of the supporting webs will be explained in describing themanufacture of the wheel.

Referring to Figure I of the drawings, it will be seen that a chill 6 isprovided in the flask surrounding the mold cavity which is to form thefelly of the wheel, and in such position that the surface constitutingthe tread of the wheel will be in contact with the chill when the metalis poured. When the metal for the wheel is poured into the mold, thechill causes rapid solidification of the metal in contact with it, thusproducing a greater hardness than would occur if the metal werepermitted to cool slowly.

It may now be noted that, because of the positioning of disk 3 and webs5, there is no body of metal extending from the hub metal to the portionof the felly adjacent the flange. This region of the felly is,therefore, not subjected to a flow of heat from the mass of molten metalconstituting the hub and the metal constituting the disk. The chilleffect, therefore, is not reduced in this region adjacent the flange ofthe wheel. but in this region remains present to a relatively greatdepth. Heat flow radially outward from the hub is concentrated directlyin the transversely outer circumferential region 20. of the felly. insubstantial degree counteracting the effect of the chill in this region,and consequently lessening in this region the depth of the; chilledeffect.

Referring to Figure IV of the drawings it will be seen that adjacent theouter edge of the felly the chilled metal of the tread formssubstantially a skin on the tread. and that the chilled eflect is ofgreatly increased depth in the tr'ead region which lies upon a rail, andin the flange of the wheel. The thickness of the chilled". metal 7extends diametrically inward from the tread in its greatest depth wherethe hardness is most needed; and since conditions are uniform throughoutthe circumference of the wheel, the depth of the chill is substantiallyuniform throughout the wheel circumference. The transversely outerregion of the wheel felly, in which the tread is subjected to less wear,is hardened to a lesser depth, so that the tread wears with substantialuniformity throughout its width, and a channeling effect in the regioncontacting the rail is prevented.

Referring again to Figure I of the drawings, it should be explained thatit is highly desirable to so prepare the mold that the flange 4 of thewheel will be lowermost in the mold. This is for the reason that withsuch arrangement the metal constituting the flange, and the portion ofthe felly adjacent the flange, comes first to rest in the mold, and theremainder of the casting metal does not substantially disturb the metalforming this region of the wheel. If the mold arrangement were reversed,molten metal flowing past the chill into position to form the hub anddisk of the wheel, and the inner portion of the felly, would heat thechill, and would also tend to heat such skin of casting metal as mightcongeal thereagainst in forming the tread and flange of the wheel.

I have found moreover that a wheel comprising a disk positioned at theouter edge of the felly, and chiefly outwardly beyond the railcontacting portion of the tread serves, when a wheel is cast as above described,to lessen stresses to such extent that such wheels need not be taken toa soaking pit after casting. This is for the reason that the flange andouter portion of the felly will solidify and shrink in advance of anyother portion of the wheel. With this metal already solidified, the massof metal remaining molten consists of the hub, which acts as a reservoirof heat, the disk, and the portion of the wheel felly in direct contactwith the disk and in communication with the hub through the disk. Asthere is a free condition of heat exchange in these regions aftersubstantial solidification of the remaining felly portion of the wheel,the inner portion of the felly, in contact with the disk throughout theentire circumference of the wheel, may follow in its shrinkage theshrinkage of the disk and hub closely enough to prevent setting upstresses sufliciently severe to necessitate soaking the wheel aftercasting. For this reason a wheel of this conformation does not sufferloss in the degree or depth of tread hardness by an annealing operationsubsequent to its cast-ing.

Inorder to increase this effect, a chill of the form shown in Figure IVmay be employed. This chill So has a region 6b of greatest thickness andheat capacity to lie against the region of the tread adjacent the flangeof the wheel. and is tapered to provide a region of lesser thickness andheat capacity adjacent the outer edge of the tread.

I have made a number of comparative hardness tests on my wheels andother chilled mine car wheels of standard form made in accordance withstandard foundry practice. I have found that, by avoiding annealing inthe soaking pit, the Brinell hardness in the highly chilled region of mywheel tread is from 25 to 40 points higher than the hardest regions (theregions between spokes) of tread in all the other Wheels. The wheelsused for these tests have been of iron substantially identical with thatcomposing my test wheels.

The extreme hardness difference taken on my tread at any circumferentialpoint adjacent the flange and at the least hardened regions of thecompared wheels (the tread regions diametrically outward of the spokes)is from to 100 points Brinell. This latter instance is due not only tothe avoidance of intentionally annealing in the soaking pit, but also tothe mold effect above described in which heat flow outwardly to thefelly is avoided in a selected transverse region of the tread.

It may be noted that there is a direct relation, in a section ofsubstantial thickness, between the depth of chilled metal and thesurface hardness. I obtain in the most highly chilled region of my wheeltread, a hardness of 514 to 520 points Brinell.

It may be noted that the depth of chilled metal in the felly of thewheel may be apportioned transversely of the tread by changes in theradius in the inner face of the disk 3 where it joins the felly of thewheel. That is, a'greater or lesser transverse region of the felly maybe in direct heat communication with the wheel hub by varying thisradius. The design of the wheel may thus be varied within limits fordifferent purposes in which the wheels are to be used, and variations inthe tread width of the wheel. i

There is, further, a positive advantage in the fact that the chilleifect is minimized at the junction of the disk and felly. This is dueto the fact that regions of cast iron retaining combined carbon, as bythe effect of the chill, possess less strength. In my wheel the strengthof the metal is greatest where strength is required, as also thehardness is greatest where hardness is requisite.

The various advantages of my wheel result from an intentionalconformation of a cast wheel such that full advantage is taken of theuse of a chill in modifying the qualities of the casting.

While a wheel of my novelform is peculiarly adapted for use on minecars, it is to be understood that its advantages are also of value forcars of various types as used in industrial plants.

I claim as my invention:

1. A wheel for mine and industrial cars made as an integral casting andcomprising a hub, a felly of substantially uniform mass throughout itscircumferential extent, a disk interconnecting the hub and felly; thedisk being positioned adjacent the outer edge of the felly and in themain outwardly beyond the inner rail-contacting region of the felly, thedisk in its connection with the felly providing the entire area ofcontact and connection with the felly by the wheel elements lyingradially inward of the felly, and reinforcing ribs extending between thehub and the disk, said wheel having a chilled tread comprised by thefelly and which tread has its depth of chill approximately uniformcircumferentially of the felly and greater in the rail contacting regionof the tread transversely beyond the region of disk contact with thefelly.

2. A cast wheel for mine and industrial cars having a hub, a flangedfelly, and connecting means therebetween integral with the hub and thefelly, a chilled tread comprised by the felly and having a depth ofchili approximately uniform circumferentially of the tread in the regionadjacent the flange of the felly, said felly having no volume of metalextending radially inward of the felly in the region adjacent the flangeof the felly, as a result of which a circumferentially uniform chillhardness in excess of five hundred on the Brinell hardness scale isattainable in that region, and reinforcing ribs extending between thehub and the means interconnecting the hub and felly out of contact withthe region of the felly adjacent the flange of the felly.

3. A wheel for mine and industrial cars made as an integral casting andcomprising a hub, a felly of substantially uniform mass throughout itscircumferential extent, a disk interconnecting the hub and felly; thedisk being positioned adjacent the outer edge of the felly and in themain outwardly beyond the inner rail-contacting region of the felly, thedisk in its connection with the felly providing the entire area ofcontact and connection with the felly by the wheel elements lyingradially inward of the felly, and at least one mass of reinforcing metalstrengthening the junction between the hub and the disk, said wheelhaving a chilled tread comprised by the felly and which tread has itsdepth of chill approximately uniform circumferentially of the felly andgreater in the rail contactingregion of the tread transversely beyondthe region of disk contact with the felly.

4. A cast wheel for mine and industrial cars having a hub, a flangedfelly, and connecting means therebetween integral with the hub and thefelly, a chilled tread comprised by the felly and having a depth ofchill approximately uniform circumferentially of the tread in the regionadjacent the flange of the telly, said felly having no volume of metalextending radially inward of the telly in the region adjacent the flangeof the felly, as a result of which a circumferentially uniform chillhardness in excess of five hundred on the Brinell hardness scale isobtainable in that region, and at least one mass of reinforcing metalstrengthening the junction between the hub and the means interconnectingthe hub and felly, said mass of reinforcing metal terminating out ofcontact with the region of the felly adjacent the flange of the felly.

ARTHUR L. LEE.

